I am always in search of
"propeller nirvana" and have run a BUNCH of them on my
big Saito 180 powered fun-fly . In APC props I have run 16x10, 18x8 and 17x6. The
APC 17x6 is the best by far for my application (
http://www.devino.org/mark/airplanepics/aeroworks.htm).
I started with a YS 120 on that plane, but Saito 180'ed it a month ago.